Vehicle steering control apparatus

Abstract

A steering control apparatus for a vehicle which prevents an interference between a steering operation performed by the steering control apparatus and a steering operation performed by a driver of the vehicle. A guide line provided on a vehicle moving lane is recognized by a forward image of the vehicle so as to set a target position on the vehicle moving lane based on a result of recognition of the guide line. A steering control operation is performed so that the vehicle moves to trace the target position. The steering control operation is started when a distance between the vehicle and the guide line is less than a first predetermined value. The steering control operation is ended when a distance between the vehicle and the guide line exceeds a second predetermined value which is greater than the first predetermined value.

What is claimed is: 
     
       1. A steering control apparatus for a vehicle comprising: guide line recognizing means for recognizing at least one guide line provided on a vehicle moving lane on which said vehicle is moving so as to set a target position on the vehicle moving lane based on a result of recognition of said guide line;   steering control means for performing a steering control operation so that said vehicle moves to trace said target position;   steering control starting means for starting the steering control operation when a distance between said vehicle and said guide line recognized by said guide line recognizing means is less than a first predetermined value; and   steering control ending means for ending the steering control operation when the distance between said vehicle and said guide line recognized by said guide line recognizing means exceeds a second predetermined value which is greater than said first predetermined value.   
     
     
       2. The steering control apparatus as claimed in claim 1, wherein said guide line recognizing means comprising: a camera which takes an image of a forward view of said vehicle; and   a guide line recognizing unit which processes the image taken by said camera so as to recognize the guide line and set the target position, said guide line recognizing unit calculating a distance between said vehicle and the guide line and an amount of offset of a present position of said vehicle from the target position.   
     
     
       3. The steering control apparatus as claimed in claim 2, wherein said steering control means includes: a steering mechanism operated by an electric motor;   steering calculating means for calculating an amount of steering to be achieved by said steering mechanism in accordance with the offset amount of said vehicle; and   a drive circuit which controls said electric motor so that the amount of steering calculated by said steering calculating means is achieved.   
     
     
       4. A steering control apparatus for a vehicle comprising: guide line recognizing means for recognizing a first guide line and a second guide line between which said vehicle is moving, said guide line recognizing means calculating a first distance between said vehicle and said first guide line and a second distance between said vehicle and said second guide line;   steering control starting means for starting a steering control operation when one of first and second conditions is satisfied, said first distance being equal to or less than a first predetermined value in said first condition, said second distance being equal to or less than a second predetermined value in said second condition; and   steering control ending means for ending the steering control operation when one of third and fourth conditions is satisfied, said first distance being greater than a third predetermined value in said third condition, said second distance being greater than a fourth predetermined value in said fourth condition, said third predetermined value being greater than said first predetermined value and said fourth predetermined value being greater than said second predetermined value.   
     
     
       5. The steering control apparatus as claimed in claim 4, wherein said guide line recognizing means comprises: a camera which takes an image of a forward view of said vehicle; and   a guide line recognizing unit which processes the image taken by said camera so as to recognize the first and second guide lines and calculate said first and second distances.